The Northwest Indian Campaigns grew out of the US-Dakota War of 1862, an event sometimes classified as part of the US Civil War and sometimes as the beginning of the Indian Wars. The conflict began on August 18, 1862, when small groups of Dakota Warriors raided white settlers living in southern Minnesota.

The Dakotas of southern Minnesota were frustrated by years of accumulated grievances against white settlers and government officials over issues relating to reservation lands and controversial administrative practices. In the preceding decade the Dakotas, who had once controlled much of what was now the state of Minnesota, had been forced to cede almost all their land in the state, retaining only a small strip south of the Minnesota River. The Dakotas were further provoked when annuity goods and cash from the US government, promised in exchange for the land cessions, were delayed. Fearing starvation after a poor harvest, and knowing government warehouses were full of food, some frustrated and angry Mdewakanton and Wahpekute Dakotas attacked farms, several settlements, Fort Ridgely along the Minnesota River in southwestern Minnesota, and Fort Abercrombie on the Red River of the North (see Fort Abercrombie State Historic Site). Most Dakotas did not join in, some choosing to aid and protect settlers, while others attempted to stay out of the conflict. Some were not even present, but were hunting in the lands west of the Red River. An estimated 450 to 800 settlers and soldiers were killed in these attacks; Dakota losses were estimated at about twenty-one.

Henry Hastings Sibley

Although approximately 40,000 white settlers fled during the initial stages of the conflict, within a few days, locally raised militia began fighting back. Due to the demands of the raging Civil War, few “regular” US troops were available for frontier service. The available state militia troops were mostly young, poorly trained, and poorly armed. However, at Wood Lake, these soldiers under the command of Colonel Henry Hastings Sibley won a significant victory, ending the fighting and raiding in Minnesota.

As the military arrested suspected perpetrators, many Dakotas, participants and non-participants alike, feared retaliation and fled to other areas. It was reported that Thaóyate Dúta (Little Crow), a principal Mdewakanton leader of the conflict, and Iŋkpáduta (Scarlet Point), a hostile Wahpekute leader, had retreated to the vicinity of Devils Lake in Dakota Territory. Others fled to other parts of Dakota Territory or to Canada. Eventually, nearly four hundred Dakotas were tried by a military tribunal for their alleged participation in the conflict; of these, 308 were sentenced to hang. President Abraham Lincoln commuted many of the death sentences, but thirty-eight of those convicted were hanged at Mankato, Minnesota, on December 26, 1862.

John Pope

Still, many Minnesotans wanted further retribution, including removal of all the Dakotas from Minnesota and continued arrests of escaped perpetrators. The distinction between Dakotas who had participated in the fighting and those who had not begun to blur. Some believed that future hostilities could be prevented only if severe punishment continued, and that the prospect of a new outbreak was likely. Approximately eight hundred Dakotas had fled the Lower Sioux reservation, and there were another 4,000 Dakotas at the more northern reservation, many of whom had vacated their villages and moved further into eastern Dakota Territory. Also, it was feared that thousands of Yanktons and Yanktonai from the eastern plains of Dakota Territory might rise up in support of their Minnesota relatives. Therefore, General John Pope, recently appointed commander of the new Military Department of the Northwest, devised a plan to trap the enemy Sioux in Dakota Territory.